The invention relates to a method for providing network failure independent links in a multilayer network comprising a client layer and a server layer.
Multilayer networks can comprise at least one client layer and a corresponding server layer which provides services to the client layer. An aspect of traffic engineering of a contemporary transport network is protecting services which the network provides for its users against various network failures such as fiber cuts, device failures, software bugs, configuration errors etc. Such protection is usually achieved in a conventional network via network over-provisioning. The topology of a multilayer network is made up of links and switching elements that can carry user traffic as well as of redundant links that have sufficient unused bandwidth to accommodate the user traffic in case that one or more of the operating or working links go unexpectedly out of service. A major challenge in the context of service protection is the fact that it is never known in advance where the failures are located or occur. Accordingly, working links and the protecting links must be selected to be independent from each other so that it is impossible for a single network failure to bring down both, a working link and the corresponding link protecting the working link.
Accordingly, there is a need for a method for providing network failure independent links in a multilayer network to provide an operative multilayer network even when working links go out of service.